Many advances have been made since the introduction of the disposable absorbent article including the introduction of wetness indicating compositions. Such compositions may comprise a colorant adapted to change in appearance, i.e., appear, disappear, change color, etc., upon contact with liquid, such as, urine, menses, in the article. Certain attempts have been made to retain the colorant, such as, incorporating the colorant into adhesive compositions having high melting temperatures.
However, there are problems associated with existing wetness indicating compositions. One problem of most, if not all, existing wetness indicating compositions is poor retention of the colorant within the composition upon contact with liquid. That is, the colorant diffuses out of, i.e., leaches from, the composition and migrates toward and possibly through portions of the absorbent article on which it is contained, e.g. the backsheet and/or topsheet of a disposable absorbent article and ultimately onto the wearer. This may lead to consumer negatives, such as, clothing or bedding staining, and/or may cause the wetness indicator to appear unsightly through the backsheet. For example, the applied pattern of the wetness indicator composition may become blurry, indistinct, or otherwise aesthetically displeasing.
Another problem is premature activation in high humidity environments, which may render the wetness indicator less effective in detecting and/or indicating the presence of liquid. For instance, exposure to a high level of humidity may partially activate wetness indicating compositions that are not highly resistant to colorant leaching and thereby make any color change in the presence of liquid less noticeable.
Finally, any wetness indicating composition attached to a substrate, such as, the backsheet of a disposable absorbent article, needs to have sufficient wet and dry cohesion and/or flexibility to be fully retained on the substrate. The normal bending, flexing and/or folding associated with the use of the substrate, such as, being worn in the case of a disposable absorbent article, puts stresses on the wetness indicating composition, possibly leading to portions of the wetness indicating composition to chip off the substrate on to which it is applied.
However, the need remains for a wetness indicating composition that is highly resistant to colorant leaching, as described above, and is resistant to premature activation in high humidity environments. Furthermore, the any wetness indicating composition attached to a substrate needs to have sufficient wet and dry cohesion and/or flexibility to be fully retained on a substrate.